Aberrant Regeneration of the Third Cranial Nerve in aPatient with Severe Head Injury

Agu Kafa Travmah Bir Hastada Aberan Uc;;iincii Sinir Rejenerasyonu

BA$AR ATALAY, $ANSAL GEDiK, HAKAN CANER,

SiBEL OTO, MURAD BAVBEK, NUR ALTINORS

Ba~kent University Faculty of Medicine, Department of Neurosurgery (BA, He, MB, NA)

Ba~kent University Faculty of Medicine, Department of Ophthalmology ($G, SO)

Received: 02.12.2002 0 Accepted: 13.01.2003

Abtract: Aberrant regeneration of the third cranial nerveis a well-known condition that can develop after headtrauma or intracranial aneurysms. Horizontal gaze-eyelidsynkinesis, pseudo-V on Graefe phenomenon, and limitedelevation and depression of the eyelid with retraction ofthe globe are common signs of aberrant regeneration ofthe third nerve. These features may appear months toyears after third nerve injury. Patients who have sufferedsevere head trauma or have had an intracranial aneurysmnear the third cranial nerve should be followed in

consultation with ophthalmologists. They should also betold about the possibility of aberrant regeneration of thisnerve, and about the features of this condition.

Key Words: Aberrant regeneration, intracranialaneurysm, third nerve palsy, trauma

INTRODUCTION

The third cranial nerve, or oculomotor nerve,

supplies most of the extraocular muscles, includingthe inferior oblique, the medial, superior andinferior recti, and the levator muscle of the upper

Ozet: Aberan ii<;iinciisinir rejenerasyonu kafa travmalanve intrakranial anevrizmalar somasmda goriilebilen iyitammlanrm~ bir durumdur. Yatay bakI~ta gozkapag,.sinkinezisi, psodo Von Graefe Bulgusu, yukan ve a~aglbakl~ klSlthhgl ve goziin i<;eri retraksiyonu aberanrejenerasyonun slk goriilen bulgulandlr. Bu bulgularii<;iincii sinir hasarmdan aylar ya da Yillar soma ortaya<;lkabilir. U<;iincii sinir felci olan aglr kafa travrnaSl veyaintrakraniyal anevrizma hastalan oftalrnologlarla birliktetakip edilmeli ve aberan rejenerasyon bulgulan hakkIndabilgilendirilmelidir.

Anahtar Kelimeler: Aberan rejenerasyon, intrakraniyalanevrizrna, travrna, ii<;iincii sinir felci

eyelid. It is responsible for ocular motility in thehorizontal, vertical and torsional planes, and forlevator function (1). In addition, the oculomotornerve carries the parasympathetic fibers to thesmooth muscles of the pupillary sphincter andciliary muscle.

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TlIrkish NeuroslIrgery 13: 49-52, 2003

The congenital and acquired forms ofoculomotor nerve palsy may be partial (one ormore muscles affected) or complete (pupillaryfunction also affected). Ptosis, a fixed and dilated

pupil, and a down-and-out resting eye position arethe classical manifestations of complete third nervepalsy (5,6,8,11). The common clinical findings ofpartial third nerve palsy are variable ptosis andparesis of ocular motility in accord with themuscles affected. Aberrant regeneration of theoculomotor nerve was first described by Cowers(4) in 1879. This condition is a well-known eyemovement disorder that usually occurs after acutethird nerve injury. Trauma and aneurysms are themost common causes of this problem (2,3,7). Herewe report a case of aberrant regeneration of thethird cranial nerve in a patient who had sufferedsevere traumatic brain injury.

CASE REPORT

A 17-year-old female presented to ourneurosurgery clinic with the complaint ofincreased frequency of epileptic fits. At the time,she was experiencing generalized tonic-clonicseizures 1-2 times weekly. Before admission shewas on phenytoin treatment and the seizures wereunder control. The patient's medical historyincluded cranial surgery at 2 years of age fortreatment of a right frontop~rietal intracerebralhematoma caused by severe head trauma. She hadstarted to have epileptic attacks at 7 years of age. Atthe age of 12 (10 years after the initial surgery), thepatient had undergone cranioplasty forreconstruction of frontoparietal bone defects.

Her neurological examination at admissionrevealed mild left-sided hemiparesis and right totaloculomotor nerve palsy. An electroencephalogramshowed right parietotemporooccipital paroxysmalepileptic activity. Cranial magnetic resonanceimaging showed encephalomalacic changes in theright frontoparietal region, a porencephalic cyst inthe right lateral ventricle, and atrophy of thecorpus callosum (Figure 1).

Treatment with 5-mg / kg / day phenytoin wasprescribed, and this brought the seizures undercontrol.

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Atala!!: Aberrallt Third Nen'e Regelleratioll

Ophthalmic Findings:

The patient's visual acuity was 20/400 in theright eye and 20/20 in the left eye. The right eyeshowed severe ptosis (Figure 2). The verticalfissure height in that eye was 4 mm, and the upperlid excursion was 2 mm. It was not possible tomeasure the margin-reflex distance, so only one­third of the iris was visible. In primary position,there was 25 PD exotropia and 6 PD hypotropia.All left eye movements appeared normal, but theright eye showed severely restricted adduction,

Figure 1. Cranial magnetic resonance imaging showedencephalomalacic changes in the rightfrontoparietal region, a porencephalic cyst inthe right lateral ventricle, and atrophy of thecorpus callosum.

Figure 2. Severe ptosis in the right eye.

Turkish Neurosurgery 13: 49-52, 2003

supraduction and infraduction (Figure 3). Forcedadduction was accompanied by retraction of theupper lid, and abduction was accompanied by liddepression. The right lid became elevated onattempted downward gaze. Results of forcedduction tests were unremarkable. Anisocoria was

noted in primary position at average room lightand under dim illumination. In room light,pupillary diameter was 5-6 mm on the right and 3mm on the left. Direct and consensual pupillarylight reflexes were absent on the right, and thediameter of the right pupil decreased to 4-5 mm onattempted downward gaze and right gaze. Slit­lamp examination revealed no segmental paresis ofthe sphincter. The patient did not exhibitnystagmus. Fundus examination with a +90 D lensshowed atrophy of the optic disc in the right eye(Figure 4).

Figure 3. Severely restricted adduction, supraductionand infraduction in the right eye.

Figure 4. Fundus examination of the right eye revealedoptic disc atrophy

Alalay: Aberranl Third Nen'e Regeneration

DISCUSSION

The incidence of aberrant regeneration of thethird nerve after acute third nerve injury is 15% (2).Head trauma and aneurysms of the posteriorcommunicating artery are the most commoncauses of this condition. Horizontal gaze-eyelidsynkinesis, pseudo- Von Graefe phenomenon(elevation of the lid on downward gaze), andlimited elevation and depression of the eye withretraction of the globe with attempted verticalmovements are common signs of aberrantregeneration of the oculomotor nerve (10). Patientsmay also show gaze-evoked pupillary constriction(pseudo-Argyll Robertson pupil). The signs ofnerve fiber misdirection may appear months toyears after the third nerve injury occurs.Misdirection of regenerating third nerve fibers,ephaptic transmission, and central synapticreorganization are the proposed mechanisms forthis condition (9).

Our patient developed aberrant regenerationof the oculomotor nerve after traumatic brain

injury. She showed full-blown signs of fibermisdirection, including elevation of the right eyelidon adduction, retraction of this eyelid ondownward gaze, limited elevation and depressionof the eye and pseudo-Argyll Robertson pupil ondownward gaze and adduction. Severe headtrauma resulted in traumatic optic disc atrophyand reduced visual acuity (20/400) in the right eye.

Aberrant regeneration of the third cranialnerve should be kept in mind as a possible latecomplication in patients who suffer severe headinjury involving the third nerve. Patients should bewarned about the possibility of nerve fibermisdirection and the potential problems that thiscauses. Follow-up should be done in consultationwith ophthalmologists.

Correspondence: Ba~ar Atalay, MDBa~kent UniversityFaculty of MedicineDepartment of NeurosurgeryFevzi <;:akmak Caddesi,06490 Bah<;eIievler,Ankara, TurkeyPhone: 212 6868/1368Fax: 223 7333E-mail: basara@baskent-ank.edu.tr

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Atalay: Aberrant Third Nerve Regelleration

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